1. Field of the Invention
The present invention generally relates to systems and methods for treating water. More particularly, the invention relates to the reduction of contaminants from wastewater using bacteria.
2. Description of the Relevant Art
Many types of natural resource production operations utilize large quantities of water to improve the efficiency of the operation. Examples of natural resource production operations that use water include, but are not limited to hydraulic fracturing operations, drilling operations, and mining operations.
In hydraulic fracturing operations, fissure, or fractures, are created in an underground formation to allow natural gas and/or oil to be extracted from the formation. The fractures are created by pumping a mixture of water, sand and other components under high pressure into the formation. The high pressure water creates fissure and cracks which allow the gas and/or oil to escape from the formation. As the gas and oil is extracted, significant amounts of wastewater may also be collected. This wastewater may be contaminated with hydrocarbons, inorganic salts, and metals.
In drilling operations, a drill bit is attached to a length of connected drilling pipe. As the drill bit is rotated, rock in contact with the bit is ground into smaller pieces. A drilling fluid (e.g., drilling mud) is circulated through the drill pipe and back to the surface, flushing the drill bit cuttings to the surface. The drilling fluid also serves to cool and lubricate the drill bit. As the cuttings are extracted, significant amounts of wastewater may be produced. This wastewater may be contaminated with hydrocarbons, inorganic salts, and metals.
In mining operations, waster may be used for drilling and milling processes. In drilling and excavation processes water may be used to cool drilling equipment and remove cuttings from the drilling/excavation site. During milling processes, water is mixed with cuttings obtained from a drilling or excavation operation to provide a medium for grinding and or milling process that reduce the particle size of the solid material suspended in the water. As the cuttings are extracted and ground or milled, significant amounts of wastewater may be produced. This wastewater may be contaminated with hydrocarbons, inorganic salts, and metals.
Water is thus essential to many operations for extracting natural resources. Most systems utilized to treat wastewater produced from natural resource production sites require large amounts of energy and maintenance. Most technologies rely on multi-stage flash distillation and/or a series of membranes to return the water to a usable state. As a result of utilizing these technologies, associated costs of water reclamation is costly to the point of being prohibitive. Multi-stage flash distillation (MSF) and membrane filtration require substantial amounts of energy, and a knowledgeable staff capable of operating the units. In the case of MSF, scaling and corrosion are frequently observed and represent a major maintenance aspect. In the case of membrane filtration, increased operational costs, reduced efficiency, and membrane fouling are often the result of treating water with increased loads of salinity.
The most common method of handling the wastewater resulting from these operations is thus disposal at approved injection wells, although recently some companies have been introducing recycling technologies at various locations. The resulting water quality of water obtained from nature resource production operations is typically not suitable for reuse without some form of treatment that removes residual pollutants (organic and inorganic). To allow for the development of more efficient natural resource production sites, water reuse systems will need to be improved and made more cost efficient.